1. Field of the Invention
This invention relates to a display device and a mobile apparatus.
2. Background Art
What is called a head-up display (HUD) is known, which uses a display device, and thereby displays various kinds of information on a front glass (windshield) of a mobile apparatus such as a vehicle and aircraft to cause an operator to view the image information together with the image of the outside background field.
As to the head-up display, the displayed optical image of image information may be viewed as a double image. When the optical image of image information is viewed as a double image, visibility is reduced.
Therefore, a technique is proposed that prevents the optical image of image information from being viewed as a double image (see JP-A-8-271827(Kokai)(1986) and JP-A-2-294615(Kokai)(1990)).
JP-A-8-271827 (1986) provides a film adjusting the direction of polarization, and configures the front surface and the back surface of a front glass so that they are nonparallel, and thereby prevents the optical image of image information from being viewed as a double image.
JP-A-2-294615 (1990) provides a film having birefringence in a front glass or inside a cabin to prevent the optical image of image information from being viewed as a double image.
However, such techniques need to make the shape of a front glass in the thickness direction a unique shape and/or to provide a special film in a front glass or inside a cabin. Therefore, they may increase cost and significantly decrease versatility.